Modern data centers house large numbers of computer servers, typically in frame racks, in which a plurality of servers are mounted in a closely spaced relation. In operation the densely arranged servers generate substantial heat, which must be removed in order to prevent overheating and malfunction of the equipment. The individual server units generally are provided with internal fans, which pull cooling air through the unit. However, because of the high density of the equipment, it is customary to provide substantial air conditioning systems to supply cooled air to the fronts of the racks, available to be drawn through the individual servers by their internal fans.
Operating efficiency of the cooling systems has become an increasing problem as the power output of the servers has been progressively increased and the expense of cooling them has become very meaningful. A significant aspect of controlling cooling costs is the prevention or minimization of mixing of the supplied cool air with warm air in the data center, without the cool air having been passed through a server and absorbed its heat. Where mixing is allowed to occur outside of the servers, the capacity of the A/C equipment must be enlarged, at increased capital expense up front, and the efficiency of the A/C equipment is compromised by the lower temperature differential between the air supplied to and delivered by the A/C equipment.
Among the techniques employed at modern data centers are hot-air-cold air aisles, hot air containment and cold air containment. For the hot-air-cold air aisles, servers are arranged side-by-side in rows. Two rows of servers are oriented back to back, with cool air being supplied to the fronts of the rows (cold aisles) and warm air being collected in the hot aisle between the two rows and returned to the A/C unit. This technique represents an improvement over previous arrangements but still permits considerable quantities of the cool air to bypass the servers and mix with warm air.
The hot air containment procedure is similar to the above but involves completely closing off the hot aisle at the top and ends, to further reduce the amount of cool air permitted to return without passing through a server, while allowing the cool air to be present generally throughout the room. Warm air from the enclosed hot aisle is ducted back to the A/C unit and a relatively high efficiency is achieved. In some cases warm air is ducted out of the backs of each of the server cabinets and returned to the A/C unit. Cold air containment is similar to the hot air containment procedure, except that the cold air is contained in an aisle space and warm air is present throughout the room. This procedure is not as widely used as hot air containment because the presence of the warm air generally throughout the room makes for an uncomfortable working environment.
Even in relatively efficient systems, such as hot air containment, there still can be significant efficiency losses. For example, in some cases the server racks may be constructed with interconnected internal and external frames. The internal frames serve to mount a plurality of servers and blanking panels and the external frames mount cover panels or doors. This arrangement, which may be referred to herein as a double frame rack, enables initial wiring of the servers to take place in an open environment, before the cover panels and doors are installed. The double frame construction, which useful for certain purposes, results in a space being formed between the servers, mounted on the internal frame elements, and cover panels, mounted on external frame elements, through which cooling air can flow to the warm side of the rack without passing internally through a server. In early installations this may not have resulted in a significant loss of efficiency, because the servers have their own internal fans intended to draw the available cool air through the servers.
Modern data room configurations, however, such as the hot air and cold air containment configurations referred to above, can result in considerable air pressure differentials between the cold and hot sides of the servers, such that there can be a meaningful bypass flow of cooling air around the servers, in the space between internal and external frame structures, notwithstanding the normal functioning of the internal server fans. Such bypass flow, and the resulting losses in operating efficiencies, have become an increasing issue as the power of the servers has been increased and along with that the power of the A/C systems and the increased pressure differentials utilized therein. There has been a definite need for sealing devices that can be quickly and easily attached to frame elements of a server rack, to seal off spaces internal and external frames of the rack and prevent the flow of bypass air at the sides of the servers and also at the bottom of the rack.